The invention relates to a cleaning device for a dust filter, having a flow duct which extends between an entry opening and an exit opening, and having an annular chamber which surrounds the flow duct and which is provided with gas-inlet connectors for the inflow of pressurized gas into the annular chamber and, towards the flow duct, is provided with nozzle gaps which are delimited by nozzle-gap walls. The annular chamber is composed of an upper annular shell and a lower annular shell which on the radial outside in a connection region are interconnected in a pressure-tight manner. The gas-inlet connectors are moulded on the upper annular shell; the lower annular shell is designed so as to be predominantly flat, extends horizontally or downwardly towards the nozzle gap and, at the same time, forms the lower nozzle-gap wall.
Cleaning devices of this type are known from KR 20/0321528 Y1 and from WO 2009/043332. Said cleaning devices operate based on the Coand{hacek over (a)} principle and are employed for cleaning the filter hoses and filter candles of dust filters, to which end the cleaning device is disposed above the filter hose which is open towards the top, or above the filter candle. A flow duct which is surrounded by an annular chamber extends between an entry opening and an exit opening. The annular chamber is supplied from above from a compressed-air reservoir. Said annular chamber is closed on the external wall and is provided on the internal wall thereof with nozzle gaps which open into the flow duct. The nozzle gaps are upwardly and downwardly delimited by nozzle gap walls.
The annular wall is formed and enclosed by two walls which in a connection region which extends along the external periphery are interconnected in a pressure-tight manner. The lower wall runs horizontally or slightly downwardly towards the nozzle gap and, at the same time, forms the lower nozzle gap wall; the upper wall determines substantially the spatial shape of the annular chamber and the volume of the annular chamber.
The potential of use of cleaning devices of this type covers all sectors in which dust filters are industrially employed. One of these sectors is the foodstuff industry, for example, the industry processing milk to milk powder. Particularly stringent hygiene requirements apply to the foodstuff industry and also to the pharmaceutical industry. An infestation with germs may arise in the case of cleaning devices for dust filters when, following wet cleaning, residues of cleaning fluid mixed with residue of product remain in individual parts of the plant. It has been observed that in the case of cleaning devices of the generic type, even where these are conceived for increased hygiene requirements, an infestation with germs may still arise under unfavourable circumstances involving tight cavities and in particular gaps. Small residues of cleaning fluid, possibly mixed with residue of product, may remain there for a prolonged time after the cleaning process.
Therefore, the object of the invention is to provide a cleaning device for a dust filter which meets even the highest hygiene requirements.